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ocsp: Fixes for gateway reconnecting and reloading #5208

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275 changes: 275 additions & 0 deletions internal/ocsp/ocsp.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,275 @@
// Copyright 2019-2024 The NATS Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package testhelper

import (
"crypto"
"crypto/tls"
"crypto/x509"
"encoding/base64"
"encoding/pem"
"fmt"
"io"
"net/http"
"os"
"strconv"
"strings"
"sync"
"testing"
"time"

"golang.org/x/crypto/ocsp"
)

const (
defaultResponseTTL = 4 * time.Second
defaultAddress = "127.0.0.1:8888"
)

func NewOCSPResponderCustomAddress(t *testing.T, issuerCertPEM, issuerKeyPEM string, addr string) *http.Server {
t.Helper()
return NewOCSPResponderBase(t, issuerCertPEM, issuerCertPEM, issuerKeyPEM, false, addr, defaultResponseTTL, "")
}

func NewOCSPResponder(t *testing.T, issuerCertPEM, issuerKeyPEM string) *http.Server {
t.Helper()
return NewOCSPResponderBase(t, issuerCertPEM, issuerCertPEM, issuerKeyPEM, false, defaultAddress, defaultResponseTTL, "")
}

func NewOCSPResponderDesignatedCustomAddress(t *testing.T, issuerCertPEM, respCertPEM, respKeyPEM string, addr string) *http.Server {
t.Helper()
return NewOCSPResponderBase(t, issuerCertPEM, respCertPEM, respKeyPEM, true, addr, defaultResponseTTL, "")
}

func NewOCSPResponderPreferringHTTPMethod(t *testing.T, issuerCertPEM, issuerKeyPEM, method string) *http.Server {
t.Helper()
return NewOCSPResponderBase(t, issuerCertPEM, issuerCertPEM, issuerKeyPEM, false, defaultAddress, defaultResponseTTL, method)
}

func NewOCSPResponderCustomTimeout(t *testing.T, issuerCertPEM, issuerKeyPEM string, responseTTL time.Duration) *http.Server {
t.Helper()
return NewOCSPResponderBase(t, issuerCertPEM, issuerCertPEM, issuerKeyPEM, false, defaultAddress, responseTTL, "")
}

func NewOCSPResponderBase(t *testing.T, issuerCertPEM, respCertPEM, respKeyPEM string, embed bool, addr string, responseTTL time.Duration, method string) *http.Server {
t.Helper()
var mu sync.Mutex
status := make(map[string]int)

issuerCert := parseCertPEM(t, issuerCertPEM)
respCert := parseCertPEM(t, respCertPEM)
respKey := parseKeyPEM(t, respKeyPEM)

mux := http.NewServeMux()
// The "/statuses/" endpoint is for directly setting a key-value pair in
// the CA's status database.
mux.HandleFunc("/statuses/", func(rw http.ResponseWriter, r *http.Request) {
defer r.Body.Close()

key := r.URL.Path[len("/statuses/"):]
switch r.Method {
case "GET":
mu.Lock()
n, ok := status[key]
if !ok {
n = ocsp.Unknown
}
mu.Unlock()

fmt.Fprintf(rw, "%s %d", key, n)
case "POST":
data, err := io.ReadAll(r.Body)
if err != nil {
http.Error(rw, err.Error(), http.StatusBadRequest)
return
}

n, err := strconv.Atoi(string(data))
if err != nil {
http.Error(rw, err.Error(), http.StatusBadRequest)
return
}

mu.Lock()
status[key] = n
mu.Unlock()

fmt.Fprintf(rw, "%s %d", key, n)
default:
http.Error(rw, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
})
// The "/" endpoint is for normal OCSP requests. This actually parses an
// OCSP status request and signs a response with a CA. Lightly based off:
// https://www.ietf.org/rfc/rfc2560.txt
mux.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) {
var reqData []byte
var err error

switch {
case r.Method == "GET":
if method != "" && r.Method != method {
http.Error(rw, "", http.StatusBadRequest)
return
}
reqData, err = base64.StdEncoding.DecodeString(r.URL.Path[1:])
case r.Method == "POST":
if method != "" && r.Method != method {
http.Error(rw, "", http.StatusBadRequest)
return
}
reqData, err = io.ReadAll(r.Body)
r.Body.Close()
default:
http.Error(rw, "Method Not Allowed", http.StatusMethodNotAllowed)
return
}
if err != nil {
http.Error(rw, err.Error(), http.StatusBadRequest)
return
}

ocspReq, err := ocsp.ParseRequest(reqData)
if err != nil {
http.Error(rw, err.Error(), http.StatusBadRequest)
return
}

mu.Lock()
n, ok := status[ocspReq.SerialNumber.String()]
if !ok {
n = ocsp.Unknown
}
mu.Unlock()

tmpl := ocsp.Response{
Status: n,
SerialNumber: ocspReq.SerialNumber,
ThisUpdate: time.Now(),
}
if responseTTL != 0 {
tmpl.NextUpdate = tmpl.ThisUpdate.Add(responseTTL)
}
if embed {
tmpl.Certificate = respCert
}
respData, err := ocsp.CreateResponse(issuerCert, respCert, tmpl, respKey)
if err != nil {
http.Error(rw, err.Error(), http.StatusInternalServerError)
return
}

rw.Header().Set("Content-Type", "application/ocsp-response")
rw.Header().Set("Content-Length", fmt.Sprint(len(respData)))

fmt.Fprint(rw, string(respData))
})

srv := &http.Server{
Addr: addr,
Handler: mux,
}
go srv.ListenAndServe()
time.Sleep(1 * time.Second)
return srv
}

func parseCertPEM(t *testing.T, certPEM string) *x509.Certificate {
t.Helper()
block := parsePEM(t, certPEM)

cert, err := x509.ParseCertificate(block.Bytes)
if err != nil {
t.Fatalf("failed to parse cert '%s': %s", certPEM, err)
}
return cert
}

func parseKeyPEM(t *testing.T, keyPEM string) crypto.Signer {
t.Helper()
block := parsePEM(t, keyPEM)

key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
key, err = x509.ParsePKCS1PrivateKey(block.Bytes)
if err != nil {
t.Fatalf("failed to parse ikey %s: %s", keyPEM, err)
}
}
keyc := key.(crypto.Signer)
return keyc
}

func parsePEM(t *testing.T, pemPath string) *pem.Block {
t.Helper()
data, err := os.ReadFile(pemPath)
if err != nil {
t.Fatal(err)
}

block, _ := pem.Decode(data)
if block == nil {
t.Fatalf("failed to decode PEM %s", pemPath)
}
return block
}

func GetOCSPStatus(s tls.ConnectionState) (*ocsp.Response, error) {
if len(s.VerifiedChains) == 0 {
return nil, fmt.Errorf("missing TLS verified chains")
}
chain := s.VerifiedChains[0]

if got, want := len(chain), 2; got < want {
return nil, fmt.Errorf("incomplete cert chain, got %d, want at least %d", got, want)
}
leaf, issuer := chain[0], chain[1]

resp, err := ocsp.ParseResponseForCert(s.OCSPResponse, leaf, issuer)
if err != nil {
return nil, fmt.Errorf("failed to parse OCSP response: %w", err)
}
if err := resp.CheckSignatureFrom(issuer); err != nil {
return resp, err
}
return resp, nil
}

func SetOCSPStatus(t *testing.T, ocspURL, certPEM string, status int) {
t.Helper()

cert := parseCertPEM(t, certPEM)

hc := &http.Client{Timeout: 10 * time.Second}
resp, err := hc.Post(
fmt.Sprintf("%s/statuses/%s", ocspURL, cert.SerialNumber),
"",
strings.NewReader(fmt.Sprint(status)),
)
if err != nil {
t.Fatal(err)
}
defer resp.Body.Close()

data, err := io.ReadAll(resp.Body)
if err != nil {
t.Fatalf("failed to read OCSP HTTP response body: %s", err)
}

if got, want := resp.Status, "200 OK"; got != want {
t.Error(strings.TrimSpace(string(data)))
t.Fatalf("unexpected OCSP HTTP set status, got %q, want %q", got, want)
}
}
42 changes: 42 additions & 0 deletions server/gateway.go
Original file line number Diff line number Diff line change
Expand Up @@ -432,6 +432,22 @@ func (g *srvGateway) updateRemotesTLSConfig(opts *Options) {
} else if opts.Gateway.TLSConfig != nil {
cfg.TLSConfig = opts.Gateway.TLSConfig.Clone()
}

// Ensure that OCSP callbacks are always setup after a reload if needed.
mustStaple := opts.OCSPConfig != nil && opts.OCSPConfig.Mode == OCSPModeAlways
if mustStaple && opts.Gateway.TLSConfig != nil {
clientCB := opts.Gateway.TLSConfig.GetClientCertificate
verifyCB := opts.Gateway.TLSConfig.VerifyConnection
if mustStaple && cfg.TLSConfig != nil {
if clientCB != nil && cfg.TLSConfig.GetClientCertificate == nil {
cfg.TLSConfig.GetClientCertificate = clientCB
}
if verifyCB != nil && cfg.TLSConfig.VerifyConnection == nil {
cfg.TLSConfig.VerifyConnection = verifyCB
}
}
}

cfg.Unlock()
}
}
Expand Down Expand Up @@ -811,10 +827,35 @@ func (s *Server) createGateway(cfg *gatewayCfg, url *url.URL, conn net.Conn) {
var timeout float64

if solicit {
var (
mustStaple = opts.OCSPConfig != nil && opts.OCSPConfig.Mode == OCSPModeAlways
clientCB func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
verifyCB func(tls.ConnectionState) error
)
// Snapshot callbacks for OCSP outside an ongoing reload which might be happening.
if mustStaple {
s.reloadMu.RLock()
s.optsMu.RLock()
clientCB = s.opts.Gateway.TLSConfig.GetClientCertificate
verifyCB = s.opts.Gateway.TLSConfig.VerifyConnection
s.optsMu.RUnlock()
s.reloadMu.RUnlock()
}

cfg.RLock()
tlsName = cfg.tlsName
tlsConfig = cfg.TLSConfig.Clone()
timeout = cfg.TLSTimeout

// Ensure that OCSP callbacks are always setup on gateway reconnect when OCSP policy is set to always.
if mustStaple {
if clientCB != nil && tlsConfig.GetClientCertificate == nil {
tlsConfig.GetClientCertificate = clientCB
}
if verifyCB != nil && tlsConfig.VerifyConnection == nil {
tlsConfig.VerifyConnection = verifyCB
}
}
cfg.RUnlock()
} else {
tlsConfig = opts.Gateway.TLSConfig
Expand Down Expand Up @@ -880,6 +921,7 @@ func (s *Server) createGateway(cfg *gatewayCfg, url *url.URL, conn net.Conn) {
// Builds and sends the CONNECT protocol for a gateway.
// Client lock held on entry.
func (c *client) sendGatewayConnect(opts *Options) {
// FIXME: This can race with updateRemotesTLSConfig
tlsRequired := c.gw.cfg.TLSConfig != nil
url := c.gw.connectURL
c.gw.connectURL = nil
Expand Down
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